x402-gated API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-protocol API marketplace that gates a variety of endpoints behind per-request micropayments settled in USDC on the Base network. The specific endpoint at `/api/v1/cards/93` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is handled via the x402 exact scheme — no API keys, no rate limits, and no subscriptions required.
The broader platform advertises four categories of endpoints: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02/request price point. However, the specific functionality behind `/api/v1/cards/93` is not documented beyond the generic "Premium API Access" label, so what this particular endpoint returns is unclear.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no detailed description of what data or service this endpoint provides. The endpoint is live and correctly returns a 402 challenge, but without documentation it is difficult to know what to send in the POST body or what response to expect.
Capabilities
Use cases
- —Accessing premium API data without needing API keys or subscriptions
- —Making one-off paid API calls settled via USDC on Base
- —Agent-driven workflows that need pay-per-request access to miscellaneous endpoints
Fit
Best for
- —Developers who want keyless, pay-per-use API access
- —AI agents with x402-compatible wallets on Base
- —Quick prototyping without subscription commitments
Not for
- —Users who need detailed API documentation or schemas before integrating
- —High-volume use cases where $0.02/request adds up significantly
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/93 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is zero documentation on what this specific endpoint does, what request body it expects, or what it returns. The docs/pricing/README pages are all blank beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —The specific functionality of /api/v1/cards/93 is undocumented — 'Premium API Access' is the only description available.
- —No OpenAPI schema, request examples, or response examples exist anywhere in the crawled material.
- —All documentation pages (docs, API, pricing, README) render only 'Connect wallet' with no usable content.
- —The broader platform lists many endpoint categories but none are documented beyond a name and price.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/cards/93
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers Data & Analytics, AI & ML, Finance & Web3, and Infrastructure endpoint categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/cards/93